I have a 1999 Bayliner 1950 with a Mercruiser 135 that quit at 30 mph. Turns out the 20 amp ignition fuse blew. Repeated attempts with new fuses blew the fuse as soon as the switch was turned to start. Local tribal knowledge led to spraying the ignition switch with WD-40, a new fuse, and it ran for an hour cruise. Ran the next day for a few hours. Went to start after a swim, and blew the fuse. The WD-40/ new fuse was tried twice with no change- blown fuses. Once last try with switch removal, thorough dousing, and a 25 amp fuse (real bad idea - but we needed to get going) and we ran home fine. That evening we did fine, including restarts. Next day OK.<br /><br />A review of other posts, which had lots of great ideas for chasing similiar problems, are not quite the same. I have trouble accepting the problem is elsewhere, if the WD-40 works. I'm planning to get a new ignition switch with a weather proof cap. I now have a large box of 20 amp fuses onboard.<br /><br />Any suggestions of what else to check would be appreciated. The general condition of the boat is very clean. The wiring seems good (no corrosion), but has some added accessory wiring that is not fully secured. I suspect a short is somewhere (possibly other than the ignition switch.) The ohmmeter idicates the switch is working fine. (Three pole plastic switch, so I don't know how it can short out, unless it is just moisture.) The switch does not appeared to be sealed.
